Inside Job

So there I was, innocently slicing up some of the salami that we made during our most recent cycle. All of a sudden, I began to see large air pockets inside the sausage:

Pretty soon, these air pockets started to show up filled with mold:

Not too appetizing, to say the least. So what happened? I think there are two problems. The first is that we hand-mixed the sausage before stuffing it into the casings. I could be wrong, but I think that instead of smushing everything together into a homogeneous ball, the hand mixing probably left large air pockets throughout. When mixing with a Kitchenaid, the entire mixture eventually gets sticky and is somewhat cohesive. The other problem is that some of these air pockets undoubtedly contained mold spores, and enough oxygen to support a small amount of growth. Note that the mold, once deprived of oxygen, stopped growing, but the water activity of the interior of the sausage was certainly high enough to support growth for a time.

There was only one sausage that fell prey to the internal mold problem. I thought it was of dubious quality throughout the drying process, because the other sausages hardened up, but it still felt squishy even after 3 weeks.

The other problem we’ve seen is a lack of consistency in the texture of the hand-mixed sausages. While the machine-mixed tuscan salami we made at first showed good definition, the ones we made this time had many large clumps of fat – too large to be dismissed as enhancing the product’s “rustic charm”. I think we’ll start another batch of dry cured sausages soon, but this time, we’ll use the kitchenaid.

5 Comments

Ahhh, the evil air pockets. Mixing the slurry by hand was not necessarily your problem. I’ve mixed salami together before by hand a few times (about 35 pounds in a 50 pound food lug) and it comes out fine.

I used to be plagued by air pockets. I was paranoid about everything from the mixing process to the stuffer to the hanging. Commercial operations actually use enormous vacuum tubs that suck all their air out before stuffing.

In the end what seems to make the biggest difference is making sure your humidity levels are correct during the hanging process. Otherwise the meat does dry along the proper gradient and the outside pulls away from the inside. If you think about it this makes much more sense than somehow large pockets of air making it through the pressure of the stuffing piston which most likely has a blow-off valve anyway.

This is where the book “Charcuterie” is just absolutely devoid of information. It’s a great start but the light will shine down from heaven when you invest in the Marianski books.

The humidity gradient is ideally about 5% below the water activity in the meat. So when the mean is first hung, yes, it’s actually right to have 85% to 90% humidity in the chamber. The secret that no one tells you is that this gradient actually happens *automatically* and even without humidification if you have the right amount of sausage in it. If you take a bunch of freshly stuffed sausages and lay them in a food lug the humidity in there will most definitely be 90%+. There’s a perfect fermentation chamber, btw. I put them in a lug, close the lid and sit the whole thing on top of a “FermWrap” heater from a brew store. 80 degrees, 90% humidity. Perfect.

Once you have fermentation you can hang but the humidity still needs to be a good 80% for the first few weeks. Again, if you’re hanging in an enclosed space like a refrigerator that can be pretty easy to achieve. A 1kg salami will actually lose between 25 and 35mL of water PER DAY so imagine all of that is diffusing into the air.

After another week or so you can drop the humidity down to 70% and leave it there for the duration.

Once I figured a few key things out my sausages came out right every time:

1. Never allow the fat to smear. Grinding up fat is best done outside in 0 degree weather or, better yet, not at all. I just grind up very cold butt and don’t bother adding in extra fat. Be VERY careful with fermentation temperatures. Go much above 80 degrees and a thin layer of fat can melt between the casing and the meat and then your drying potential is over. If I had a nickel for the times I screwed that up.

Commercial operations often use bowl cutters, not grinders, which is a totally different effect. If they do grind they are grinding in refrigerated rooms and sometimes even add dry ice to the slurry (pretty clever, eh?).

2. Books talk about “lean pork butt” but I can’t for the life of me understand what that is supposed to mean. Pork butt is NOT lean and is already at about 25-30% fat. I just cube it up and grind it and it works every time. Great way to not smear the fat.

3. Control the amount of added liquid. Wine gives great flavor but the more liquid you add the more it has to dry. Sometimes that is desirable if you want a more wrinkled casing or you want the bacteria to have more time to do their magic. I usually stick to about 25mL/kg but that can safely double if you want a longer drying time or a funkier shape.

4. Use the proper humidity gradients. Your life will improve dramatically

5. Because of #4 use penicillin on everything. You mentioned in a previous entry that you don’t HAVE to have white mold on the surface. No, no you don’t, but the tricks to achieving that are many and varied while the easy way out is simple. If you rub your sausages down with penicillin first you’ve nothing to worry about for the whole time.

A friend on the analysis end of salumi making led me to this interesting blog.

While I agree with Stoozie on several of the answers to the questions posed, I differ with others.

Air pockets are of course a problem in salami; they can destroy one’s hard work in a few short weeks, as seen in the photos. Given the right conditions, ambient, aggressive, opportunistic, hydrophilic molds such as those shown in the photos will establish themselves in an instant. Externally, they are not of much concern, but internally, it’s the end.

Air pockets are formed in pâte (the seasoned ground meat mixture that goes in the casing) that has not been carefully tamped down inside the stuffer canister. They are passed through the stuffer tube, and into the casing as it’s filled. The release valve isn’t designed to remove air pockets from the pâte; its main purpose is to allow air to escape from the canister so the pressure inside the canister doesn’t push back against the crank, making it hard to turn. That pressure can also cause emulsification of the fat and lower the quality of you product.

Air pockets will not be corrected by adjusting relative humidity in the drying box; they have to be physically eliminated. The beauty of a professional hydraulic stuffer is the complete elimination of air in the pâte. If noticed, they can be corrected at twisting or tying time, but it is very difficult to be sure the air has been eliminated. The safe approach is to empty the casing and repack.

Proper salt level is a critical factor, as it acts a binding agent on the myoglobin. You want a sticky pâte. You might check that to be sure you’re at the correct level. Minimum is around 2.5%.

Another important factor is mixing. Proper mixing develops the stickiness and ensures an even distribution of ingredients. You have to be careful not to over mix and smear the fat, and this is where temperature becomes very important. Try to keep the temp below 42ºF (5.5ºC) by chilling your grinding and mixing equipment well (even the bowl), and starting with well chilled meat. An old school method of testing for sufficient stickiness is to see if a small ball of pâte sticks to your downward facing palm.

As Stooxie points out, temperature is very important. Though I have not seen the dry ice method used commercially, wet ice is often used to effect a certain amount of emulsification and to lower the temperature of the pâte. Large commercial operations will grind frozen meat, precluding the need for added ice (and thereby, added water), and controlling the rise in temperature during grinding.

Of course, smearing, the result of the fat temperature being too high at grinding or mixing, is a potential problem to avoid. To this end, all meat and fat should be cold to begin with, and held on ice as you work; all grinding equipment should be assembled then well chilled in ice water until you’re ready to grind. Ideally, you should place your cubed meat in the freezer for one to one-and-a-half hours to firm it before grinding. This also ensures the clean cutting of meat and fat in the grinder. Chilling the meat to around 28ºF (-2ºC) is ideal. The advantage of a professional, chilled workroom is obvious.

The term “lean pork” is used in the industry to differentiate pork trimmed of external fat (hard shoulder fat); undesirable soft fat between the muscles; tendon and sinew; and silver skin (fascia) from the shoulder. As Stooxie points out, shoulder has a relatively high intramuscular fat content that can run as high as 35 or 40%. Sometimes leg meat is used in certain recipes to lower intramuscular fat and obtain leaner meat. The meat and fat are measured separately as means of control; added fat can be precisely weighed, which results in greater control of the product, and greater consistency from batch to batch; professionally, this is critical. So while the phrase “lean pork” may seem like an oxymoron, it isn’t, really.

I have never had a problem with added liquid. In fact, my recipe for Toscano (black peppercorns, garlic, and red wine) calls for 350 ml wine for 4.5 kg of meat, which translates to almost 80 ml liquid per kg of meat. The result is a slight increase in drying time but it is not significant.

There are many difficulties in home salami making. Professional equipment and curing conditions make life a lot easier, but paying attention to some of these techniques will increase your chances of making really delicious salami, without air pockets, on a consistent basis.

Thank you for your helpful and timely insights, Christopher. I appreciate the tips, especially since we are about to start in on a couple of batches that we will be curing. I’ll keep careful watch over both the temperature and the mixing process.

Jansz – Thanks for the comment. The question isn’t easy to answer. We have had situations where the humidity in the fridge has been too high (I think this is what you mean by “saturated”) and where it’s too low. The fridge itself will always fight to get moisture out of the air – that’s just the way fridges are designed. Slurries made of salt and water help because they act as a buffer, but you need a relatively large vessel filled with this in order to control adequately. It will also depend on your fridge. Try a few things and see what works – the key is to find some way to measure humidity. Good luck.